Terminal device, base station device, and communication method

1. A terminal device that communicates with a base station device, the terminal device comprising:

a higher layer processor configured to perform one or more second physical downlink control channel (PDCCH) settings through signaling of a higher layer from the base station device;

a receiver configured to monitor only a common search space and a terminal device-specific search space in a first PDCCH in a case in which the second PDCCH setting is not performed, and monitor a terminal device-specific search space in at least a second PDCCH in a case in which the second PDCCH setting is performed; and

a transmitter configured to transmit capability information which indicates whether or not a physical downlink shared channel (PDSCH) scheduled by the second PDCCH can be scheduled by the first PDCCH,

wherein the first PDCCH is transmitted on a basis of a sub frame defined in accordance with a predetermined number of symbols, and

wherein the second PDCCH is transmitted on a basis of an extended sub frame of a smaller number of symbols than a number of symbols corresponding to the sub frame, and a resource block set through the second PDCCH setting.

2. The terminal device according to claim 1 , wherein

the receiver does not monitor the terminal device-specific search space in the first PDCCH in the case in which the second PDCCH setting is performed.

3. The terminal device according to claim 1 , wherein

the receiver further monitors the common search space in the first PDCCH in the case in which the second PDCCH setting is performed.

4. The terminal device according to claim 1 , wherein

the receiver further monitors a common search space in the second PDCCH in the case in which the second PDCCH setting is performed.

5. The terminal device according to claim 1 , wherein

a combination of settable values of a resource block used for transmission of the second PDCCH is decided on a basis of a number of symbols of the extended sub frame set through the second PDCCH setting.

6. The terminal device according to claim 5 , wherein

a minimum value included in the combination of the settable values increases as the number of symbols of the extended sub frame decreases.

7. A base station device that communicates with a terminal device, the base station device comprising:

a higher layer processor configured to perform one or more second physical downlink control channel (PDCCH) settings in the terminal device through signaling of a higher layer; and

a transmitter configured to map a first PDCCH to a common search space or a terminal device-specific search space in the first PDCCH and transmit the first PDCCH in a case in which the second PDCCH setting is not performed, and map a second PDCCH to a terminal device-specific search space in at least the second PDCCH and transmit the second PDCCH in a case in which the second PDCCH setting is performed, wherein the first PDCCH is transmitted on a basis of a sub frame defined in accordance with a predetermined number of symbols,

wherein the second PDCCH is transmitted on a basis of an extended sub frame of a smaller number of symbols than a number of symbols corresponding to the sub frame, and a resource block set through the second PDCCH setting, and

wherein the terminal device transmits capability information which indicates whether or not a physical downlink shared channel (PDSCH) scheduled by the second PDCCH can be scheduled by the first PDCCH.

8. A communication method used in a terminal device that communicates with a base station device, the communication method comprising:

performing one or more second physical downlink control channel (PDCCH) settings through signaling of a higher layer from the base station device;

monitoring only a common search space and a terminal device-specific search space in a first PDCCH in a case in which the second PDCCH setting is not performed, and monitoring a terminal device-specific search space in at least a second PDCCH in a case in which the second PDCCH setting is performed; and

transmitting capability information which indicates whether or not a physical downlink shared channel (PDSCH) scheduled by the second PDCCH can be scheduled by the first PDCCH,

wherein the first PDCCH is transmitted on a basis of a sub frame defined in accordance with a predetermined number of symbols, and

wherein the second PDCCH is transmitted on a basis of an extended sub frame of a smaller number of symbols than a number of symbols corresponding to the sub frame, and a resource block set through the second PDCCH setting.

9. A communication method used in a base station device that communicates with a terminal device, the communication method comprising:

performing one or more second physical downlink control channel (PDCCH) settings in the terminal device through signaling of a higher layer; and

mapping a first PDCCH to a common search space or a terminal device-specific search space in the first PDCCH and transmitting the first PDCCH in a case in which the second PDCCH setting is not performed, and mapping a second PDCCH to a terminal device-specific search space in at least the second PDCCH and transmitting the second PDCCH in a case in which the second PDCCH setting is performed,

wherein the first PDCCH is transmitted on a basis of a sub frame defined in accordance with a predetermined number of symbols,

wherein the second PDCCH is transmitted on a basis of an extended sub frame of a smaller number of symbols than a number of symbols corresponding to the sub frame, and a resource block set through the second PDCCH setting, and

wherein the terminal device transmits capability information which indicates whether or not a physical downlink shared channel (PDSCH) scheduled by the second PDCCH can be scheduled by the first PDCCH.